[Characteristics and dynamics of HIV-1 subtype distribution among injected drug users in Guangzhou, 2008 - 2015]

Objective: To understand the characteristics and dynamics of individuals with HIV-1 subtype infection among injected drug users (HIV infection IDU) in Guangzhou between 2008 and 2015. Methods: HIV-1 RNAs were extracted from serum samples of the individuals that were newly diagnosed with HIV-1 infection among IDUs living in Guangzhou, between 2008 and 2015. The Pol gene segments of HIV-1 genome from these RNA samples were amplified by nested reverse transcription polymerase chain reaction (Nested-PCR) and sequenced. Subsequently, phylogenetic tree was reconstructed using both pol sequences of samples and references before the subtype of HIV-1 was determined. Distributions of HIV-1 subtypes detected in IDUs with different demographic characteristics in different years were compared. Results: A total of 437 pol gene segments were successfully obtained from 517 serum samples of HIV infection IDUs. The average age of 437 HIV infected IDUs was 37.37 years with standard deviation as 8.17 years. 51.5% (225/437) of the HIV infected IDU that registered residence were not in Guangdong. The Guangxi Registered residents were accounted for 54.2% (122/225). Proportion of subtype CRF07_BC (46.5%) appeared the highest, followed by CRF01_AE (24.3%), CRF08_BC (23.3%) and other subtypes (5.9%). The annual proportions of subtype CRF07_BC (trend χ(2)=19.703, P=0.006) and CRF08_BC (trend χ(2)=25.718, P=0.001) were significantly different. The proportion of subtype CRF07_BC decreased from 56.9% to 34.2% (trend χ(2)=15.139, P=0.000), while the proportion of CRF08_BC increased from 11.8% to 37.0% (trend χ(2)=22.577, P=0.000). The proportion of CRF08_BC was significantly higher in the HIV infected IDUs with Guangxi residence (Monte Carlo simulation of exact probability P=0.000, 99%CI: 0.000-0.000). Conclusions: CRF07_BC, CRF01_ AE and CRF08_BC were the predominant HIV-1 subtypes while multiple subtypes were co-circulated among the HIV infected IDUs in Guangzhou, between 2008 and 2015. Behavioral intervention set for HIV infected IDUs with Guangxi residence should be strengthened in Guangzhou.